


Overprotective Rin Onii Chan

by MuNSTER



Category: Free!
Genre: Cute, F/M, Fluff, Fluff and Humor, Gen, Love, Overprotective Big Brother Matsuoka Rin, Secret Relationship, Secrets, Shock, Siblings
Language: English
Status: Completed
Published: 2019-05-18
Updated: 2019-05-18
Packaged: 2020-03-07 09:04:44
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,748
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18870061
Author URL: https://archiveofourown.org/users/MuNSTER/pseuds/MuNSTER
Summary: Gou has been acting quite out of character these days and Rin is hell bound to find out why.A fluff oneshot.





	Overprotective Rin Onii Chan

**Author's Note:**

> I don't own Free! or any of its characters.

 

 -

Although he was away from her all these years, he still managed to notice how much she had changed. Her burgundy hair in a high pony and that smile that was capable of melting anyone in the room. Her personality, not as childish as it used to be and her grit towards her swim club. Hey being a manager is not easy yet she had learned to cope with it. He was simply proud of her but could not help but feel accountable about the fact that he had missed out on her entire childhood.

His sister has changed both mentally and emotionally and he was not there with her.

But the changes that he was starting to notice in her were not how mature she had turned but they were related to her strange behavior these days.

Of how much time she had started to spend in her room or the way she is always on her phone.

The most recent occurence was when he went to give her a surprise visit at her school after his swim practice, only to find out she had left as they had the day off from their own club activities. He did manage to get home by catching the last train but was even more bewildered to find his sister right across him in the station. She should have reached home hours ago but there she was. When he asked about this she blurted out about being with Hana-Chan. 

Another thing that troubled him was how she would literally disappear almost every weekend and would return home pretty late.

 

The same goes for this Saturday, she was again missing when he reached home. His mother simply shrugged and informed him that she was at a group study with Chigusa and a few other classmates. 

Rin just brushed it off.

Or atleast he tried to.

 

_She is no longer a kid, she can handle herself Rin_

 

Was what he would constantly remind himself.

He ran his slender fingers through his maroon locks and was about to walk out of the kitchen when the woman's voice stopped him.

 

_"Ah Rin"_

 

She started. Her eyes shifting from the dishes towards her son.

 

_"Makoto-kun called about thirty minutes. He said you were not picking up."_

 

The early morning practices have been a real nuisance to deal with. Though Rin wasn’t complaining but currently he was regretting his decision of asking their previous captain to join them over the summer vacation.

 When Seijuro suggested that they should try the Training from hell regime before trying something else, the terrified expressions of his teammates should have been a hint enough for him to turn down the special workout schedule, but it was already too late and he soon found out that the ginger wasn’t joking when he named it. The upperclassman also added no one, not even the current captain himself, can miss this 5am-you-better-come-or-I-will-kick-your-ass practice.

He had overslept and must have left his cell phone back as he rushed out of the house with single bread topped with peanut butter as his breakfast.

 Walking into his room he soon found the object where he had left it the previous night; on top of his bedside table. Throwing his gym bag across the room, he crashed on top of his bed with a light thud. Reaching for his phone he scrolled through his home screen looking for any important notifications.

_3 missed calls_

 

 Two were from Makoto while he didn’t recognize the third number. He didn’t always get many calls from anonymous numbers and but when he did they were mostly from some fanboy or fangirl asking him out on a date or something. It was really tiresome to him so he overlooked the unidentified caller and proceeded to call his friend.

He effortlessly placed his muscular arm over his eyes to block the harsh sun rays as they entered his room through the window and waited for the brunet to answer the call. He felt way too lazy to get up from the comfortable mattress and close the curtains. Maybe he needed a nap.

 

A few rings and the other side finally answered.

 

_“Yo Makoto what’s up”_

 

The boy tried his best not to sound too tired but he was sure he had been yawning a lot.

 

_“Ah Rin we were wondering would you like to join us over for a small get together at the burger place right next to the station”_

 

The redhead could faintly hear Nagisa’s cheers and announcements about some kind of an eating contest followed by huff-puff and yelps in the background. He concluded that Rei was there, once again dragged by Nagisa. From what he could hear it was certain that the boys were having fun. But the idea didn’t seem to interest him at all. He was going to turn down the offer, eat something and get back to bed to have a relaxing nap.

 

_“I think you might be tired due to the early morning practice Gou-Chan mentioned earlier”_

_Gou?_

 

_Wasn’t she supposed to be at her friend’s house for group study or something?_

_“Where did you meet her?”_

 

The older Matsuoka questioned as he walked towards the window finally closing the curtains thereby prohibiting the rays to enter the room anymore.  The curtains finally being closed the redhead sat at the edge of his bed patiently waiting for Tachibana to answer.

_“At the beach about an hour ago”_

 

 The brunet replied.

_The beach?_

 

It was very unlikely that Gou, someone who can hardly swim and also has a strong repulsion to getting tan easily or getting sand all over her, would actually like the beach in general. He still remembers the time when he tried to throw her into the sea but ended up getting a lot of scratch marks all over his own body.

 His train of thoughts was interrupted when he heard Nagisa’s childish voice on the other side.

 

_“Ne ne Rin-Chan come over. The more people we have the more fun it would be.”_

 

Rin was always surprised at how was the blond able to convince anyone into doing anything. There must have been some kind of magic in the boy’s puppy dog eyes that worked on anyone who stood in front of him. Well, it won’t work on him this time.

 

_“Aren’t four people enough?”_

 

Rin laid back on the soft surface once again.

 

_“But Haru-Chan is not with us”_

 

 The boy continued his whining that the more people there is the more fun it would be and they should take a break once in a while and how amazing the weather outside was today and they should enjoy it rather than fall asleep in their rooms.

 

_“Please na Rin-Chan. You have got to try this new double jalapeno spicy burger here. Nee neee neee Rin-Chan you should enjoy your youth before you turn into an old man. And...”_

 

There was a short pause for a while before the boy’s usual lively voice was replaced with a dismayed one.

 

_“We haven’t had a chance to spend time with  you.”_

Rin sighed in defeat. There was no way he could win against Nagisa. No one could. He was aware that this was the boy’s intention to blackmail him into joining them. And the shota had won.

 

_“I will be there in twenty minutes.”_

He could already tell this was going to be a long day. At least a hot and spicy double jalapeño burger can give him the energy to deal with it.

.

.

.

 

_“A club pizza, four of the ultra-grand super spicy French fries with my regular Sugary Cupcake collection please”_

 

Taking account of his elfin self, one might be shocked to even think that Nagisa can actually eat this much. They didn’t understand how but he sure as hell can do a lot of things even his friends were not aware of. The shota had always been able to baffle others with his secret abilities and the dumbest plans ever. Yet he never failed to amaze them.

 

_“For such a short person Nagisa-Kun does eat a lot”_

_“That was rude Rei-Chan”_

 

The blond pouted, sulking in further into his seat next to Makoto. The motherly Makoto-Kun simply smiled at those two.

 

He didn’t even have to ask why Haru was not with them. Maybe be he declined the offer to stay inside the tub and enjoy a plate of roasted fish. That was his ideal way to spend a day after all. Athletes are supposed to be very active and must at all cost take care of their body but Haru was not like the others, after all he could eat mackerel and still manage to win a freestyle race against various people.

 

 It had been at least fifteen minutes since he had arrived and Rin cannot comprehend why the place was so crowded. As if understanding the puzzled look on the boy’s face Makoto informed him about the newly released movie _"A Rat's life 2"_ and the theatres were filled with people, families, couples, and friends.

 

_That was a great movie_

 

The Samezuka captain recalls the time he and Sousuke watched the movie together. The last scene was able to drag him to streams of tears.

 

Glancing out of the window Rin spotted a something or more importantly someone. A familiar shade of scarlet standing next to his childhood best friend.

 

_Gou and Sousuke?_

 

_Maybe I should ask her what she was doing here._

 

After excusing himself from the rest, he walked out through the glass doors to confront his sister. She would never lie to him.

 

_Right?_

 

As much as he despised this thought, it was starting to suspect that his sister might actually have a boyfriend. Though his sister has so far only shown interest in muscles rather than the person, but what if someone with spectacular muscles asked her out. She might even agree in order to touch that physique every single day. He wasn’t opposed to the idea of her finding a suitor but what did bother him was what kind of a person did she would be dating.

 

Upon reaching the exit he realized the girl had already left the spot and the fact that the street was packed with so many people simply made it impossible to find her. He decided he should better call her and ask where she was. He can meet up with her if she was close by.

 

 

Walking through the busy crowd he suddenly bumped into someone causing them to drop their groceries on the ground. Followed by the necessary _I'm sorry, let me help you._

 

He looked up to find it was Chigusa. The brunette was shopping for the upcoming festival and was on her way back home. They exchanged a few customary words. Chigusa lips somehow let the words _"Gou admires you a lot”_ slip out of them and Rin, the kind of older brother he is, flashed his shark teeth clearly fueled with pure delight.

 

He arched a crimson brow as the brunette informed him she hadn't seen Gou all day, but soon slapped her hands across her mouth as if she had just let something highly confidential skid out. She hastily bows her head and left before the redhead could ask anything else.

 

_She wasn’t with Chigusa then where is she??_

 

He really had to talk to her right now.

 

Scratch the previous line; he would never ever let somebody date his baby sister. Moreover, she is too precious for anyone.

 

He brushed his face with his slender fingers.

 

_I don’t have my phone on me again._

 

He felt frustrated as suspension grew inside him. There was a possibility that Gou lied about the group study thing, an excuse she used to meet his best friend.

 

_Were they on a date?_

 

That last thought suddenly unconfined waves of thunder through his mind. His sister was taking a step towards the future as a grown woman and he didn't even know. His mind was filled up with sweet childhood memories followed by a grown-up Gou as he, her Onii-chan, walks her down the aisle with Sousuke on the other side.

 

_What if she leaves him behind?_

 

The guys have already parted ways by now but the sentence was still stuck in his mind as he wandered the streets before coming across a cherry blossom tree. The leaves were slightly pink but the majorities were still green.

 

_A pool filled with cherry blossoms_

 

 The past had always come back to scare him. But his friends were there for him and the moment he stood there at the pool held close by them, he felt like he was forgiven and everything that had happened was forgotten in an instant. He enjoyed the day more than he had wished for, Rin felt like there was something missing as he walked on the path he was familiar with before entering a store.

 

Swinging the mackerel containing bag he stood before the Nanase Resident. The teen would hate to admit it but he was a little unhappy when the raven did not show up.

 

Even though he had practically banged on the door, no one had answered. He thought that Haru would be at home at this hour being the inert person he is rather than be outside, socializing with strangers. The dolphin, a name given to the swimmer by Nagisa, was probably asleep inside his bathtub and was in no mood to talk to anyone.

 

Leaving the bag right outside his door the male turned on his hills and was about to cross the front gate when the door behind him abruptly opened.

 

_“You sure took a lot of time Haru”_

 

Rin commented but laying his eyes on the person before him he realized something was really really off.

 

Haruka was standing before him in a half-sleeved white shirt with the front buttons opened with his hair in complete disarray. It even looked like the boy was exercise but Haru would always choose a submerged in the bathtub experience rather than work out.

 

Rin eventually realized what was wrong when his eyes reached the side of Haru’s neck. The white skin was painted with numerous dark red marks and all Rin could do was smirk at the state of his friend.

 

_“What is it R-Rin??”_

 

_Makoto sure knows how to tease_

 

The annoyed expression that spanned over the lad’s face made the redhead laugh, now it made clear sense as to why didn’t Haru answer the door as he always did. Too busy in finding some kind of a remark to throw at his friend, Rin didn’t notice that the boy had closed the door behind him.

_“Didn’t know you had it in ya”_

 

_“Shut up”_

 

The redhead was well aware that his friend won’t be able to give him company at the moment as he was already preoccupied with someone.

 

Flashing his sharp teeth, Rin whispered a silent _“Good luck man”_   and was waiting for Haruka to make some kind of a sarcastic comeback but the lad only hummed a _Hmm_ towards him.

 

It was almost midnight and Rin was sure that his sister is definitely hiding something from him. That evening when he returned back from Iwatobi he found Gou haven't even reached home. Tension started to swirl inside his mind for some reason and he called her.

 

This time she did answer but the conversation was mostly held from his side as his sister only said she. And when she reached home she barely made eye contact with her brother she even skipped dinner. He had wanted to ask her where she was but didn’t get the right opportunity to do so.

 

_2:30am_

 

The red digits of his clock showed.

 _I should ask her friend or the guys from the club to know what has she been up to these days_.

 

Shutting his eyes he heard the door across the hall open and close. He expected the sound of running water from the tap or at least the bathroom door to make that creaking sound but there was nothing.

 

He felt himself jolt up as he vaguely heard the front door open and close really fast and raced down the stairs almost losing his balance to find that his sister’s shoes were gone.

 

Over a million thoughts crossed his mind.

 

_Where was she going at this hour?_

_Was she meeting up with her boyfriend or worse does she have a husband?_

_Are they eloping?_

_Maybe a man in his early forties, he must have blackmailed my poor sister?_

 

_What if she has a family of her own that she was hiding from us?_

_What is if her husband occasionally beats her and my niece and nephe-_

 

Shaking his head at his wild imagination Rin thought of simply following her and watch what she is doing.

 

After multiple turns, he watched as the girl entered an indoor pool.

 

_Huh?_

 

He recalled that she said she had the keys to an indoor stadium closeby and he was free to use it whenever she wanted, he questioned her of how she came across the key her reply was Coach Goro entrusted her with it.

 

_What if Goro was the one?_

 

He cringed at this thought. There is no way his sister would even think about going out with a pervy old geezer.

 

Looking through the area he made into the building without being noticed by his sibling who was somewhere in there.

 

Searching for his sister he stopped dead in his tracks staring at the scene displayed before him.

 

_This has got to be a hallucination. Yes, my mind is playing tricks on me; I haven’t had a decent sleep in days._

 

She was sitting at the edge of the pool, her hair landing on the hard cold floor as her legs were dipped inside the pool. She was looking down to something. The lights were turned off but he could still make out a pair of muscular arms around his sister’s waist while it seemed like her arms were resting on the male’s shoulder. He could not identify who the person was as Gou was right in front of him. But he would soon find out who the person was and how he would pierce through his skin without staining indigo pool maroon.

 

**_“GOU”_ **

 

His voice echoed through the empty building gathering the pair’s attention to the intruder.

The group animatedly froze looking at each other. Gou could feel her soul slipping out of her body and Rin was completely stupefied with his jaws wide open, while Haru, well he had his usual unreadable mien.

 

He sighed. Pulling himself out of the pool he knew that he was about to be chased across the universe by a red shark and wearing clothes would at least make it look a little decent, not like a pervert running away from someone’s angry husband.

 

The couple stood before Rin as Gou explained that they have been dating for about six months, their mom knew about it too, she would not always sneak out like this,it was just for tonight and how she was the one who asked their mother not to say anything about their relationship to his former teammate.

 

_“I was about to tell you Onii-chan”_

 

She finished.

 

Lifting her eyes to look at her brother she finds him looking past her at the end of the pool with his lips slightly parted.

 

Waving her hands in front of him or shaking him was not helpful either. There was no response at all.

 

_“I broke my brother”_

 

She concluded.

 

_“Maybe we should leave him, Kou”_

 

This was all it took for his girlfriend's brother to snap back to reality.

 

 The following hour went on as the overprotective brother chased after his sister's secret boyfriend throughout the building, while Gou just sat at the nearby bench.  After the chaos inside was settled, with Rin accepting their relationship and sharing in his opinion some of his words of wisdom, more precisely you better not make my sister cry.However, the determination in his eyes was proof enough that this man loved his sister a lot.

 The older Matsuoka smiled, a smile filled with happiness and warmth. He was happy that his sister had found someone who would cherish her and that was all he could ever ask for.

 

_“He loves you”_

 

These words that her brother uttered when they were on the road ready to get back caused her features to achieve the fiftieth shade of red. From the corner of his eyes, Rin observed as his sister blushed and muttered: _“I love him too”._

 

But the question that was still unanswered was why she was with Sousuke the other day.

.

_“Ah, Haruka-Senpai and I bumped into Sousuke-Kun. That reminds me he had changed his number and was unable to get to you, he did give me his number but I think I left it back in my purse.”_

 

_Oh that explains the unknown caller_

 

He made a mental note to register the number in his contacts before falling asleep.

 

_“Where were you yesterday?”_

 

He did know the answer to that yet he felt the need to ask.

 

_“I was with Haruka-Senpai all day”_

 

The girl nervously rubbed the back of her neck; she looked so cute when she does that.

 

_See I already kne-_

_Wait_

 

_“The whole day?”_

_“Hmm”_

 

Slowly the events that occurred flashed before his eyes.

 

The time Rin visited Haru’s house.

 

_She was with him._

 

And how the boy stood before the door like a sentry as if he didn’t want Rin to look inside.

 

_She was inside that means her shoes were right there too. Haru must have closed the door so that I could not see them._

 

He remembered Haru’s flushed profile, his shirt which looked like it was put on in hurry, messy hair and those trails of hickeys on his skin. He was completely out of breath too.

This time it was Rin’s face that was drained out of colors.Sensing that something was wrong with her brother again, Gou called out to him. His face was as white as a sheet, the one someone makes when they have seen a ghost.

 

_“Onii-Chan?”_

 

She tried again.

 

_It wasn’t Makoto, it was his sister._

 

That is when Rin recalled another thing. He had basically congratulated and also wished his friend good luck for havin-

 

**_“HARUKA”_ **

**Author's Note:**

> Author's note:
> 
> Hello ^_^
> 
> Hope you guys liked it.  
> I have had this idea for quite a while now,in fact I wrote this when I was super bored during a family vacation.I had always wanted to write some thing like this and I think I like it a little. Everyone loves an overprotective Rin Chan,don't they.  
> Thanks for reading.  
> And feel free to leave your comments about anything,any grammatic mistakes or anything else.


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